[转帖]实现基本JPEG的压缩和编码
%%%%%%%%%% 实现基本JPEG的压缩和编码 %%%%%%%%%%%%% 1． 首先通过DCT变换去除数据冗余；
% 2． 使用量化表对DCT系数进行量化；
% 3． 对量化后的系数进行Huffman编码。
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
clear;
clc;
%%%%%%%%%%%%%%%%%%%%%%
%%1．主程序
%%%%%%%%%%%%%%%%%%%%%%
I=imread('lenna.bmp');
yiq=rgb2ntsc(I); % transform RGB to NTSC
my=[16 11 10 16 24 40 51 61;
12 12 14 19 26 58 60 55;
14 13 16 24 40 57 69 56;
14 17 22 29 51 87 80 62;
18 22 37 56 68 109 103 77;
24 35 55 64 81 104 113 92;
49 64 78 87 103 121 120 101;
72 92 95 98 112 100 103 99];
miq=[17 18 24 47 99 99 99 99;
18 21 26 66 99 99 99 99;
24 26 56 99 99 99 99 99;
47 66 99 99 99 99 99 99;
99 99 99 99 99 99 99 99;
99 99 99 99 99 99 99 99;
99 99 99 99 99 99 99 99;
99 99 99 99 99 99 99 99];
I1=yiq(:, :, 1);
I2=yiq(:, :, 2);
=size(I1);
t1=8;
ti1=1;
while (t1<(m+8))
t1=t1+8;
ti1=ti1+1;
end
t2=8;
ti2=1;
while (t2<(n+8))
t2=t2+8;
ti2=ti2+1;
end
times=0;
for k=0:ti1-2
for j=0:ti2-2
dct8x8(I1(k*8+1:k*8+8,j*8+1:j*8+8),my,times*64+1);
dct8x8(I2(k*8+1:k*8+8,j*8+1:j*8+8),miq,times*64+1);
times=times+1;
end
block(I2(k*8+1:k*8+8,j*8+1:t2),, 'dctmtx(8)');
end
for j=0:ti2-2
dct8x8(I1(k*8+1:t1,j*8+1:j*8+8),times*64+1);
times=times+1;
end
dct8x8(I1(k*8+1:t1,j*8+1:t2),times*64+1);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%2．function dct8x8(I,m,s) %定义DCT量化子程序
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function dct8x8(I,m,s)
T=inline('dctmtx(8)');
y=blkproc(I,,T);
y=round(y./m);
p=1;te=1;
while (p<=64)
for q=1:te
y1(s+p)=y(te-q+1,q);p=p+1;
end
for q=te:-1:1
y1(s+p)=y(te-q+1,q);p=p+1;
end
end
f=haffman(y1);
c(s:s+64,1)=f(:,1);
c(s:s+64,2)=f(:,2);
c(s:s+64,3)=f(:,3)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%3．function c=haffman(I) %定义Huffman编码子程序
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
=size(I);
p1=1;
s=m*n;
for k=1:m
for h=1:n
f=0;
for b=1:p1-1
if (c(b,1)==I(k,h))
f=1;
break;
end
end
if (f==0)
c(p1,1)=I(k,h);
p1=p1+1;
end
end
end
for g=1:p1-1
p(g)=0;c(g,2)=0;
for k=1:m
for h=1:n
if (c(g,1)==I(k,h))
p(g)=p(g)+1;
end
end
end
p(g)=p(g)/s;
end
pn=0;po=1;
while (1)
if(pn>=1.0)
break;
else
=min(p(1:p1-1));
p(p2)=1.1;
=min(p(1:p1-1));
p(p3)=1.1;
pn=pm+pm2;
p(p1)=pn;
tree(po,1)=p2;
tree(po,2)=p3;
po=po+1;
p1=p1+1;
end
end
for k=1:po-1
tt=k;
m1=1;
if (or(tree(k,1)<9,tree(k,2)<9))
if (tree(k,1)<9)
c(tree(k,1),2)=c(tree(k,1),2)+m1;
m2=1;
while(tt)
m1=m1*2;
for h=tt:po-1
if (tree(h,1)==tt+g)
c(tree(k,1),2)=c(tree(k,1),2)+m1;
m2=m2+1;
tt=h;
break;
elseif (tree(h,2)==tt+g)
m2=m2+1;
tt=h;
break;
end
end
end
c(tree(k,1),3)=m2;
end
tt=k;
m1=1;
if (tree(k,2)<9)
m2=1;
while (tt)
m1=m1*2;
for h=tt:po-1
if (tree(h,1)==tt+g)
c(tree(k,2),2)=c(tree(k,2),2)+m1;
m2=m2+1;
tt=h;
break;
elseif (tree(l,2)==tt+g)
m2=m2+1,
tt=h;
break;
end
end
dct8x8(I1(k*8+1:k*8+8,j*8+1:j*8+8),my,times*64+1);
dct8x8(I2(k*8+1:k*8+8,j*8+1:j*8+8),miq,times*64+1);
times=times+1;
end
c(tree(k,2),3)=m2;
end
end
end
[ 本帖最后由 suffer 于 2006-10-9 20:50 编辑 ]
求助
<P>好象有问题啊，不能运行？哪位大大能给修改修改，小弟先在这里谢了</P> 不能运行的主要问题可能是子程序没有分开，不过我发现部分语句出现问题。比如times，被定义成了函数，又定义成了变量。呵呵。需要再调试。
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